update on ife research at llnlaries.ucsd.edu/lib/meetings/0310-iaea-ife-crp/meier.pdf ·...

Update on IFE Research at LLNLWayne Meier, Ryan Abbott, John Barnard, Andy Bayramian,Camille Bibeau, Debbie Callahan, Alex Friedman, Mike Key,

Jeff Latkowski, Steve Payne, John Perkins, Susana Reyes, Max Tabak

IAEA Research Coordination MeetingCRP on Elements of IFE Power Plants

November 4-7, 2003Vienna, Austria

Work performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Outline

• Introduction• National Ignition Facility• Targets• Drivers (heavy ion accelerators and lasers)• Chambers and power plant assessments

LLNL conducts a wide variety of IFE related R&D activities

• The National Ignition Facility is being constructed at LLNL and had started experiments.

• Target physics activities include target designs and experimentsfor direct drive with lasers, indirect drive with heavy ions, and fast ignition.

• A high average power Diode Pumped Solid State Laser (DPSSL) is being developed at LLNL.

• LLNL is a partner in the development of a heavy ion driver. LLNL work includes magnet development, source/injector experiments, and beam and systems modeling.

• We also have activities on chamber design, fusion materials, safety and environment, and systems modeling.

The National Ignition Facility (NIF) will prove the scientific feasibility of ignition and energy gain in the laboratory

1st Beam line – 12/02Full NIF – FY08-09Ignition – FY11-12

JDL FESAC IFE 10/28-29/03

Target Fabrication•Capsules•Cryo layering in hohlraums

Target Design

Diag. techniq.,initial tuning

96 beam tests,2-cone tuning Final

symmetrytuning

Integrated 96beam tests

Optimize Tr

Diag.techniques

Implosion Diagnostics

Shock timing

Ablator tests Final shocktiming

Ignition campaign

Sub-scale& full scalenon-cryo implosions

Firstcluster

& 8-fold2-cones Full NIF

40-00-0997-1989S23BVW/cld

40-00-0997-1989H23RHS/cld 40-00-0997-1989P

23BVW/cld

Beams: 4 48 120 192

Ignition

Large Plasma Experimentswith beam smoothing

Symmetry measurement & controlHigh Convergence Implosions

Shock Timing diag. developmentAblator characterization

Omega

Optimize beam smoothing

Symmetry

IgnitionImplosions

Shock Physics

10 11 120907FY02 03 04 05 06 08

Cooling ring

Cryogenic fuel layer

Capsule ablatorHeater ring

Heat-flow coupler

He + H2 fill

Heat-flow coupler

HOHLRAUM

Cryostat

Cooling ring

13

Trad diagnostic techniquesHohlraumEnergetics

Firstquad

MP-1a

The indirect drive Ignition Plan makes use of existingfacilities, and early NIF, to optimize the ignition design

One critical mission for the National Ignition Facility (NIF) is to compress a DT target to fusion ignition

NIF laser has been optimized for maximum Joules per shot in several nanoseconds• Architecture: Flash lamp pumped Nd:glass oriented at Brewster’s angle

Inertial Fusion Energy (IFE) will require much higher shot rate and efficiency• Efficiency: 0.5 % >5 %• Shot rate: 1 shot / 4 hours 10 shots / second

Callahan 2/03–1

The hybrid target allows much larger beam spots than previous designs but requires shims to get adequate symmetry

The hybrid target allows much larger beam spots The hybrid target allows much larger beam spots than previous designs but requires shims to get than previous designs but requires shims to get adequate symmetryadequate symmetry

• For Gaussian beams, > 50% of the energy is deposited behind the shine shield

• Radiation flow around the shine shield results in a bright source near the peak of P4

• A shim layer was used to fix this asymmetry

Hybrid target6.7 MJ, G~ 60

Distributed radiator target5.9 MJ, Gain ~ 70

3.8 x 5.4 mm

1.8 x 4.15 mm

Callahan 2/03–2

We are planning an experiment on Z to test that a shim can take out the P4 asymmetryWe are planning an experiment on Z to test that a We are planning an experiment on Z to test that a shim can take out the Pshim can take out the P44 asymmetryasymmetry

Density contours

If shims are successful, they can also be used inindirect drive targets for Z-pinches or lasers

Callahan 2/03–3

Simple estimates suggest that using ions to compress fuel for fast ignition drops the ion peak power to 70-160 TW

Simple estimates suggest that using ions to Simple estimates suggest that using ions to compress fuel for fast ignition drops the ion peak compress fuel for fast ignition drops the ion peak power to 70power to 70--160 TW160 TW

150 eV 120 eV DistributedRadiator

Ebean 2.7 MJ 1.9 MJ 5.9 MJ

Power 160 TW 68 TW 550 TW

Eign(@30%)

150 kJ 600 kJ ---

Gain 160 140 68

A first estimate of driver cost suggests that the 150 eV casereduces the driver cost by 40% and the COE by 25%

Ionbeams

Ignitor beam

Through Innovative Laser Pulse Shaping we have Significantly Improved the Stability of High-Gain Direct-Drive Targets for Inertial Fusion Energy

Yield 350MJ

Elaser 2.9MJ

Gain 120

Shell breakup fraction:- Standard pulse ~1.8- Picket pulse ~0.15

DT gas

DT fuel

2.38mm DT ablator (+ CH foam)

1.0

0.1

0.01

0.001 Time

KrF or DPSSL laser

“Picket stake” prepulse

Laser Power Pulse Shape

LASNEX 2D Stability Results

Standard

Standard pulse

Picket pulseGro

wth

rate

(e-f

olds

)

ICC2003

The original FI concept uses laser generated MeV electrons to ignite DT fuel at about 300 gcm-3

10 kJ, 10 ps

Hole boring Ignition

1 MeV electrons heat DT fuel to 10 keV 300 g/cc

Fast ignition

Light pressure bores hole in coronal plasma

Ignition spot energy

E = 140 (100/ρ)1.8 kJ

e.g. ρ=300 g cm-3, E=17 kJ

in <20 ps

to r=19 µm hot spot

at 7x1019 Wcm-2

Atzeni. Phys. Plas. 6 3316 (1999)

100 kJ, 20 ps Hole boringor cone for laser to penetrate close to dense fuel

Pre-compressedfuel 300 gcm-3

Tabak et al. Phys Plasmas 1,1626,(1994)

ICC2003

Proton ignition is a newer concept avoiding the complexity of electron energy transport

• Same driver and fuel assembly options

•Larger laser focal spot-easier to produce

• Simpler proton energy transport by ballistic focussing

Imploded Fuel

Laser Protons

• Novel physics of Debye sheath proton acceleration

M. Roth et.al.Phys Rev. Lett 86,436 (2000).

Ruhl et al. Plas. Phys. Rep.27,363,(2001)

Temporal, et al.Phys Plasmas 9, 3102, 2002

ICC2003

-400 -200 0 200 400 600

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

Distance (microns)

Tim

e (n

s)

480 500 520 540 560 580 600

071802#4 Hemisphere

-400 -200 0 200 400 600

-0.40

-0.30

-0.20

-0.10

-0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

Distance (microns)

Tim

e (n

s)

480 490 500 510 520

071802#5 flat foil

First demonstration of ballistic proton focusing was made recently with the LLNL JanUSP laser

50 µm200µm >400µm

Streak images of Planckian emission

Focused beam gives 7.7x more temp rise (20 eV) than unfocused

Focused protons give 2 to 3 x more heating

than direct heatingby electrons

ICC2003

Fast ignition targets are designed with radiation /hydro- codes and tested at the Omega laser

(1) Shell /cone interface hydroentrainment of cone material

(2) Preheat of cone ahead of imploding shell

(3) Cone tip-dense core transport distance

(4) Avoidance of ‘hollow centre’in compressed core

Validate fuel assembly concepts in ‘hydro- equivalent’ targets

(1)(2)

(3) (4)

(5) Drive symmetry and surface smoothness requirements

(5)

(5)

ICC2003

3.0 ns 3.1 3.2 3.3 3.4

Design of cone targets was developed using modeling with Lasnex

Simulated sequence of radiographs at Omega

Lasnex model of Imploded density Radiograph

400 µm

Au cone

Cone target at Omega

"Design and Analysis of Cone-Focussed Fast Ignition Experiments",Hatchett, S.P., et al. 2002, Bull. Am. Phys. Soc.,47, 85.

ICC2003

A ‘proof of principle ‘ FI experiment at NIF has been designed using Lasnex modeling

FR-2

250kJ Hohlraum drive with8 fold 2 cone symmetry (8 quads per LEH)

4 HEPW ignitor beams total of 20kJ, 20psdriving electron or proton ignition

CD shell 740 µm radius 160 µm wall Imploded to45 µm radius, 250 gcm-3

ρr =1.o gcm-2

ICC2003

High gain fast ignition experiments using 100 kJ of HEPW would require 5 quads of HEPW beams

NIF could be adapted to demonstratehigh gain fast ignition

Solid state laser driver requirements for inertial fusion energy (IFE)

1) Efficiency > 5 - 10 %, including cooling• Key issue is recycled power in power plant for laser driver

2) Overall cost < $500/J for 2 MJ laser driver• Requires diode price of 5¢/Wpk (< $0.5B for 2 MJ driver)

3) Repetition rate of 5 - 10 Hz• Limited by clearing rate of chamber

4) Reliability of >108 shots• ~1010 needed for diode arrays; >108 shots for other components

5) Pulse width of 3 nsec and wavelength of < 0.4 µm (I.e. use tripling)• Needed to compress target to ignition

6) Beam smoothness of σ < 0.1 % in 1 nsec on-target • Beam quality must be < 12 xDL to allow for smoothing to be applied

7) Architecture scalable to multi-kilojoule class per beam line• Beam energy impacts brightness and coherence, and system integration

Output

Gas-cooledamplifier head• He gas flow at 0.1 Mach

Diode arrays• 6400 diodes total (900 nm)• 640 kW peak power

Crystals• 7 Yb3+:Sr5(PO4)3F slabs

in each amplifier head

Front-end• 300 mJ

Mercury Laser is proceeding toward its goals - one amplifier head of the laser has been activated thus far

Output





Front-end• 300 mJ

Output





Front-end• 300 mJ

Goals:• 100 J at 1ω• 10 Hz• 10% Efficiency• 3 ns• < 5X Diffraction limit• > 108 shots

Components of the Mercury Laser will allowrep-rated, efficient operation

Flash lamps Laser diodesHigher efficiency

and reliability

Convective cooling Forced gasAllows 10-Hz

operation

Gas

Nd:glass Yb:crystalsIncreased energy

storage and efficiency

boule

slab

Pump

Laser beam

Brewsters angle Normal incidence amplifierCompact optical arrangment

Vanes

Injection and beam reverser

Pump delivery anddiode arrays

Gas-cooled amplifier head

Front endDiode

pulsers

Mercury Laser has been operated reliably in single-shot and rep-rated modes

200 400 600 800 1000 120005

10152025303540

7 slab data Model

Out

put E

nerg

y (J

)

Diode Pulsewidth (µs)0 5 10 15 20 25 30 35 40

048

1216202428

Out

put E

nerg

y (J

)

Number of Shots (x 103)

5 Hz50 W

5 Hz76 W

10 Hz97 W

5 Hz89 W

5 Hz114 W

0 5 10 15 20 25 30 35 40048

1216202428

Out

put E

nerg

y (J

)

Number of Shots (x 103)

5 Hz50 W

5 Hz76 W

10 Hz97 W

5 Hz89 W

5 Hz114 W

Average Power

-6 -4 -2 0 2 4 60.00

0.01

0.02

0.03

0.04

0.05

0.06 Width Height

Varia

nce,

σ (c

m)

Distance (cm)

96% of energy 5 XDL (114 W)

With a single amplifier, Mercury was operatedat up to 34 J single shot, and 114 W average power at 5 Hz

Model

Data

Energetics

Horizontal dataM2 = 6.3

Beamwaist(cm)

Vertical dataM2 = 2.8

The 2-amplifier system will enable 100 J operation

Goals: (performance to date)• 100 J at 1ω (24J, 34J SS)• 10 Hz (5-10Hz)• 10% Efficiency (4%)• 2-10 ns (15ns)• < 5X Diffraction limit (5X rms)• > 108 shots (104)

Output

Gas-cooledamplifier heads• Helium gas flow at 0.1 Mach

Diode arrays• 8 diode arrays• 6624 diodes total (900 nm)• 730 kW peak power (110W/bar)


in each amplifier headFront-end• 300 mJ

Pump delivery anddiode arrays

Gas-cooled amplifier

heads

Front end

We are currently commissioning the second amplifier needed to achieve 100 J

Learning curve analysis suggests that diode bar prices will drop as the market grows, and can reach price of < 5 ¢ / W for a fusion economy

• IFE plant uses ~25,000,000 bars operating at 400 W / bar• “Bottoms-up” estimate of diode bars is ~3 ¢/W• Semiconductor industry “minimum function” can have ~60% learning curve

• IEEE Spectrum, June 1980, p.45

10k 100k 1M 10M 100M0.01

0.10

1.00

10.00

100.00Pr

ice

( $ /

W )

Cumulative # of bars

19941995

19961997

2001

Mercury price

2007

2020

IFE goal

“Soft” quote of 35 ¢/W

59% learning curveLow duty

cycle diode bars

overall height of stack is 59" = 1.5 mlength of individual assemblies = 259" = 6.5 m

11x16 cm slabs are separated by .75" = 2cmcenterline to centerline distance between amplifier assemblies is 60“ = 1.5 m

overall width of 7 amplifiers is 410" = 10.4m

• 12 aperture beamline fed by cooling lines (water and helium), and mounted on space frame structure• 7 beamlines can be serviced by each water and helium utility• Beams are re-formatted to a nearly square beam for transport to chamber

IFE beamline involves linear bundling of 12 apertures

The Heavy Ion Fusion Virtual National Laboratory

Heavy-ion beam requirements flow from designs of accelerators, chambers and targets that work together

Buncher Finalfocus

Chambertransport TargetIon source

& injector Accelerator

Beams at high current and sufficient

brightness to focus

Long lasting, thick-liquid protected chambers for 300 MJ fusion pulses

@ 5 Hz (See talk by Tillack)

High gain targets that can be produced at low cost

and injected (See talks by Lindl, Nobile, Campbell)

A self-consistent HIF power plant

study was recently

published in Fusion Science

and Technology, 44, p266-273 (Sept. 2003)

Beam brightness Bn τ > 4x106 A.s/(m2rad2) at target


Heavy ions can apply to a variety of targets, chambers, and focusing schemes, but a key motivation is the desirability of using thick liquid-protected fusion chambers with much reduced materials development

Granular-Solid Flow Protected

Wall

Direct Drive,Aspherical

High GradientLine Linacs

Solid DryWall

Pinch ModesIndirect Drive,Fast ignition

InductionRecirculator

Thin-Liquid-Protected Wall

Ballistic,Vacuum

Indirect Drive,Hybrid Target

RF Linac +Storage Ring

Thick-Liquid-Protected Wall

Ballistic, Neutralized

Indirect Drive,Distributed

Radiator

Induction Linac

ChamberFocusingTargetAccelerator

Approaches emphasized in the U.S. program (primary emphasis) (secondary)


Example of critical physics issue: drift compression of bunch length by factors of 10 to 30

Perveance

Final FocusDrift compression line

Induction acceleration is most efficient at τpulse ~100 to 300 ns Target capsule

implosion times require beam drive

pulses ~ 10 ns Bunch tail has a few percent higher

velocity than the head to allow compression in a drift line

Issues that need more study and experiments:

1. Matching beam focusing and space-charge forces during compression.

2. Beam heating due to compression (conservation of longitudinal invariant)

3. Chromatic focus aberrations due to velocity spread

The beam must be confined radially and compressed longitudinally against its space-charge forces


Source-Injector Test Stand (STS – operating at LLNL)

80 kV, 1.9 mT

0.000

0.005

0.010

0.015

0.020

0.025

2.5 3 3.5 4 4.5Current (mA)

Beamlet brightness measurement meets

IFE requirement

Injector Brightness:source brightness, aberration control with apertures, beamlet merging effects

0 5 10 15 200.0

0.5

1.0

ZZ (m)

0.5 m

Merging-beamlet simulation

εx, ε

y (π

-mm

-mr a

d)

(Recent paper submitted for publication in Review of Scientific Instruments. Simulation published Jan 2003 Phys. Rev Special

Topics-Accelerators and Beams)


High Current Experiment (HXC- operating at LBNL)

ESQ injectorMarx

Matching and diagnostics

10 ES quads

End Diagnostics

Low εn ~ 0.5 π mm-mr (negligible growth as simulations predict)

•Envelope parameters within tolereances for matched beam transport

1 MeV K+ on SS target, baked overnight & run at 220 C (1-8-03)

0

50

100

150

76 78 80 82 84 86 88 90Angle of incidence (deg.)

N_e/N_b6.06/cos

New Gas-Electron Source Diagnostic (GESD) shows secondary electrons per ion

lost follows theory (red curve)Four magnetic quadrupoles and additional diagnostics have been recently added to study gas and secondary electron effects

Propagation of longitudinal perturbation

launched at t = 0.

(Recently submitted for publication in Physical Review Special Topics-

Accelerators and Beams)


Neutralized Transport Experiment (NTX- operating at LBNL)

Focusing magnets

Pulsed arc plasma source

Drift tubeScintillating glass

Space charge blow-up causes large 1-2 cm focal spotswithout plasma

Smaller 1 to 2 mm focal spot sizes with plasma are consistent with WARP/LSP PIC simulations.

(Submitted for publication in Physical Review Special Topics- Accelerator and Beam Physics)

400 kV Marx / injector

. Envelope simulation

of NTX focusing with and without plasma

Superconducting magnet development

Four prototypes were fabricated and tested

• The LLNL design was selected for further development (December 2001)

• A cryostat housing two quads, and one optimized prototype magnetwas fabricated in FY02

AML

LLNL


Understanding how the beam distribution evolves passing sequentially through each region requires an integrated experiment

NTX-focusing

HCX-transport

STS-injection

The beam is collisionless, with a “long memory”

Its distribution function --- and its focusablity --- integrate the effects of applied and space-charge forces along the entire system

NOW NEXT

A source-to-target integrated beam experiment

(IBX) which sends a high current beam through

injection, acceleration, drift compression, and final

focus

Combine these elements and add acceleration and

drift compression

JFL—9/03 3rd IFSA

XAPPER MissionXAPPER Mission

XAPPER is to perform rep-rated, x-ray exposures to look for “sub-threshold” effects such as roughening and thermomechanical fatigue.

XAPPER provides large doses of soft (100-400 eV) x-rays; Dose is a reasonable figure of merit, not fluence.

XAPPER cannot match exact x-ray spectrum, but it can replicate a selected figure of merit. For example, the peak surface temperature, dose, stress, etc. that would occur in a real IFE system can be matched on XAPPER.

XAPPER will be used in the study of x-ray damage to optics and chamber wall materials.

JFL—9/03 3rd IFSA

PLEX LLC produces a sourcePLEX LLC produces a sourcethat meets our needsthat meets our needs

Uses a Z-pinch to produce x-rays:– Pinch initiated by ~100 kA from thyratrons– Operation single shot mode up to 10 Hz– Use of a focusing optic helps keep debris off samples– Several million pulses before minor maintenance

Z-pinchplasma

Ellipsoidalcondenser

Sample plane

Z-pinchplasma

Ellipsoidalcondenser

Sample plane

JFL—9/03 3rd IFSA

The XAPPER experiment is used to study The XAPPER experiment is used to study damage from repdamage from rep--rated xrated x--ray exposureray exposure

Source built by PLEX LLC; delivered 10/02; operational 11/02; system testing and characterization now complete

Operates with Xe (113 eV), Ar(250-300 eV), N2 (430 eV)

Use of foil comb helps keep debris from optic and samples

InIn--situsitu optics damage testing is underwayoptics damage testing is underway

Goal: Observe optic being damaged in real time and in-situ

Concept: Following x-ray pulse, interrogation beam (HeNe) injected, sent off auxiliary mirror, strikes sample mirror, returns, and is sent to CCD

JFL—9/03 3rd IFSA

CCDcamera

X-ray source

He-Ne laser

Beam expander

Beam splitter

Mirror two (exposed)

Mirror one (unexposed)

Neutrons can cause damage thatNeutrons can cause damage thatleads to optical absorption leads to optical absorption

2 keV Recoil in Fused Silica (0.4% OH Content)

ODCNBOHC

Structural Defects

0.07 ps

Replacement

1.36 psJFL 3/14/02

• Neutrons alter the structure of the optical material; defects absorb a portion of the laser energy during subsequent pulses

• Effect measured experimentally and modeled computationally; two items work in our favor:• Concentration of damage saturates at

relatively low doses• Damage can be thermally annealed

• Still, optical absorption in transmissive optics pushes design towards reflective or very thin transmissive optics

Effects of lower neutron damage limit were investigated for the HYLIFE-II chamber

• Pumping power increases with decreasing damage limit for a fixed wall life.

• Longer lifetimes require a thicker fluid layer and higher pumping power.

• A wall life greater than 10 years gives a cost of electricity within ~5% of full 30 year wall life.

0 5 10 15 20 25 30 35 4010

20

30

40

50

60

70

100 dpa50 dpa25 dpa

FSW Life (yr)

Hyd

raul

ic P

ower

(MW

)

0 5 10 15 20 25 30 35

1

1.1

1.2

1.3

1.4

100 dpa50 dpa25 dpa

FSW Life (yrs)

Nor

mal

ized

CO

E

Pumping Power Normalized COE

Detailed HYLIFE-II parametric CAD has been developed

Chamber construction features were developed to allow for ease of maintenance

• Broad features of maintenance scheme– Depends only on vertical cranes and simple

robotic manipulators– Does not compromise any functional

capability of previous chamber– Most internal components assembled as a

single modular unit to be replaced in entirety– All structures down to first-wall easily

accessible

UCB lecture - WRM 4/2/02 32

Work has progressed to detailed 3D neutronics models - predicting >30 year magnet lifetime

12

34

56 1

23

45

60.00E+00

5.00E+18

1.00E+19

1.50E+19

2.00E+19

2.50E+19

• There is a strong peaking of the fast neutron fluence at the center of the magnet array due to neutron scattering between neighboring penetrations.

• Estimated magnet life is 40-90 years depending on beam-to-structure clearance.

3D Tart model for HYLIFE-IIFast neutron flux for 36 magnet array

UCB lecture - WRM 4/2/02 36

Accident analyses have been completed for HYLIFE-II and SOMBRERO

SOMBRRO• Loss-of-flow with simultaneous loss-of-vacuum accident analyzed (worst case accident)• Key Result: Simple modifications reduce off-site dose to acceptable level. Graphite oxidation is an issue.

HYLIFE-II•Loss-of-flow and loss-of-coolant accidents analyzed•Key Result: Accident dose = 0.5 rem (average weather conditions and ground release) which meets no-evacuation criteria

Temperature history with decay heat and oxidation

200

400

600

800

1000

1200

1400

0 5 10 15 20

First wallInner shield

Tem

pera

ture

(C)

Time (days)

Summary

• LLNL is conducting R&D in many areas related to the development of IFE

• Work covers many approaches including– Direct-drive, indirect-drive and fast-ignition targets– Laser and heavy-ion drivers– Thick-liquid-wall and dry-wall chambers

• Other activities include– Material issues for first walls and optics– Systems modeling and integration– Neutronics, activation, safety and environmental assessments

update on ife research at llnlaries.ucsd.edu/lib/meetings/0310-iaea-ife-crp/meier.pdf ·...

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